package li;

public class day98 {
    public static void main(String[] args) {
        String  s="abc";
        String s2=s+"def";
        System.out.println(s2);
        System.out.println("------------------");
        StringBuilder sb=new StringBuilder("abc");
        sb.append("def");
        System.out.println(sb);
        System.out.println(sb.reverse());
        String ss=sb.toString();
        System.out.println(ss);
    }

}
